ABSTRACT
Water deficits can alter vital physiological functions and negatively affect plant growth. These effects can be intensified by weeds competing for water available to crops. The objective of this study was to evaluate the effects of competition and temporary soil water deficit on the transpiration (E), stomatal conductance (gs) and photosynthetic rate (A) of corn, Urochloa decumbens, and Bidens pilosa L. The experimental design was in randomized blocks with eight repetitions. The treatments were arranged in a 5 x 2 factorial scheme, with the first factor corresponding to the species: corn + U. decumbens, corn + B. pilosa, and corn, U. decumbens, and B. pilosa without competition. The second factor was two water regimes: daily irrigation and water restriction, which corresponded to the suspension of irrigation from the beginning of the V3 stage of corn until the time when their stomata were completely closed. The species B. pilosa and U. decumbens worsened the negative effects on E, gs, and A of corn at different intensities under water restriction. The U. decumbens was more aggressive in relation to B. pilosa while coexisting with corn in both water regimes. The competition with corn affected the E and gs of U. decumbens in the two water regimes, but the A was altered under water deficit. On the other hand, the physiological components of B. pilosa were not affected by its coexistence with corn in the two water regimes.
Key words:
Zea mays L.; Urochloa decumbens; Bidens pilosa L.
Thumbnail
Thumbnail
Thumbnail
Thumbnail
Thumbnail
Thumbnail
The uppercase letters compare the competition between plants and the lowercase letters compare the water regimes within each species at p ≤ 0.05 by the Tukey test. Bars indicate the standard error of the mean. The arrows indicate the timing of the return of irrigation
The uppercase letters compare the competition between plants and the lowercase letters compare the water regimes within each species at p ≤ 0.05 by the Tukey test. Bars indicate the standard error of the mean. The arrows indicate the timing of the return of irrigation
The upercase letters compare the competition between plants and the lowercase letters compare the water regimes within each species at p ≤ 0.05 by the Tukey test. Bars indicate the standard error of the mean. The arrows indicate the timing of the return of irrigation
The uppercase letters compare the competition between plants and the lowercase letters compare the water regimes within each species at p ≤ 0.05 by the Tukey test. Bars indicate the standard error of the mean. The arrows indicate the timing of the return of irrigation
The uppercase letters compare the competition between plants and the lowercase letters compare the water regimes within each species at p ≤ 0.05 by the Tukey test. Bars indicate the standard error of the mean. The arrows indicate the timing of the return of irrigation
The uppercase letters compare the competition between plants and the lowercase letters compare the water regimes within each species at p ≤ 0.05 by the Tukey test. Bars indicate the standard error of the mean. The arrows indicate the timing of the return of irrigation